Structural Explanations Research Articles

Imperforate tracheary element classification for studies of xylem structure-function relations

Summary Discovering how xylem function emerges from xylem structure requires approaches that are distinct from those invented for wood identification. I exemplify this need for different approaches by discussing the classification of imperforate tracheary elements, the cells that go by names such as “fibers,” tracheids, fiber-tracheids, and libriform fibers. Currently, there are two classification systems, one for wood identification and one championed by Sherwin Carlquist for research on xylem function. I emphasize that neither is globally “correct” for all applications, but instead each is appropriate for the aims of its field. Wood identification uses an easily-applied classification of imperforate tracheary elements, designed to remain stable over the long term. This stability allows anatomists to build large databases of wood data that are maximally useful for wood identification. In contrast, functional xylem biologists need flexible definitions that serve as hypotheses of imperforate tracheary element function to be tested, modified, and tested again, in an open-ended process of refining knowledge of xylem structure-function relations. I highlight some of the many open questions that the functional classification points to, such as the morphological correlates of the conductive/nonconductive imperforate tracheary element distinction, how imperforate tracheary element features are associated with vessel grouping, whether the libriform fiber-fiber tracheid distinction is arbitrary or not, and other topics. Recognizing that the purpose of a functional classification is to drive research shifts focus away from debates about whether a given cell type classification is “correct” and onto the empirical priorities that need study. While there is a solid tradition within comparative wood anatomy of training in wood identification, there is a need to train functional comparative wood anatomists, who can guide and interact with xylem physiologists to build more robust explanations of xylem structure and function.

‘A constant battle’: the interaction of government discourse, poverty and child and family social work practice

ABSTRACT This 2017 study explores social workers’ perspectives on the interaction of UK government discourse, poverty, and social work practice with families since the 2007–08 economic crash. This has continued relevance in today’s economic climate when the number of families in poverty is increasing. This small-scale qualitative study used interviews with social workers undertaking assessments in statutory children and young people’s service in one inner-London borough, analysed using thematic analysis. Conducted for a Social Work Masters dissertation, the study finds social workers hold structural explanations for poverty, and feel themselves to be in conflict with the prevailing individualising poverty discourse. Approaches to financial talk with families risk foreclosing the possibility of open discussion and unintentionally reinforce stigma. The sense of conflict in working within the austerity climate bears an emotional toll on participants.

Structural explanations: impossibilities vs failures

Structural explanations: impossibilities vs failures

Multidimensionalism, Resistance, and The Demographic Problem

Linda Martín Alcoff and others have emphasised that the discipline of philosophy suffers from a ‘demographic problem’. The persistence of this problem is partly the consequence of various forms of resistance to efforts to address the demographic problem. Such resistance is complex and takes many forms and could be responded to in different ways. In this paper, I argue that our attempts to explain and understand the phenomenon of resistance should use a kind of explanatory pluralism that, following Quassim Cassam, I call multidimensionalism. I describe four general kinds of resistance and consider varying explanations, focusing on those focused on vices and social structures. I argue that vice-explanations and structural- explanations are both mutually consistent and mutually entailing. If so, there is no need to choose between vice explanations and structural explanations or any other kinds of explanation. We can and should be multidimensionalists: using many together is better.

Interpreting the location data extracted from the Apple Health database

Smart fitness tracking devices are becoming more prevalent in criminal investigations. The Apple Health database for Apple Watch and iPhone fitness activity contains a diverse range of digital traces such as exercise or location information. In this paper, we provide an explanation of the database structure and an SQLite query-based approach for as complete database structure oversight as possible. We extract and link time zones to timestamps and limited geo-coordinate data to workout activity, in the context of case studies using a rich 5+ year long real database of one of the authors. Additionally we investigate the impacts of a major iOS change with iOS 16 on these insights to deepen the understanding of the data at hand. We found that the accuracy of geolocation coordinates, time zone entries, and workout information may not necessarily be accurate or consistent and requires contextual interpretation. We demonstrate the forensic value of the database in the context of informing an investigation by establishing context to a victim's or suspect's activities.

Rethinking merit? The development of more progressive approaches to university admissions in England

This paper explores how highly selective universities in England have responded to the Office for Students' call to make faster progress on widening access by 'rethinking how merit is judged in admissions' (OfS 2019: 8). Our analysis of the Access and Participation Plans (APPs) for 2020/21 to 2024/25 submitted to the Office for Students shows that England's most academically selective universities have committed to much more ambitious widening access targets than ever before. We also find that these universities have begun to articulate more structural explanations of socioeconomic inequalities in prior attainment; are making greater use of contextualised approaches to admissions; and are beginning to acknowledge the role they must play in supporting disadvantaged students to succeed at university. We argue that this represents the fragile beginnings of an important shift away from the traditional meritocratic model of admissions, in which university places go to the most highly qualified applicants irrespective of socioeconomic background, towards a more progressive model of admissions that seeks a greater degree of distributive fairness.

:Studying While Black: Race, Education and Emancipation in South African Universities

:<i>Studying While Black: Race, Education and Emancipation in South African Universities</i>

Securitizing the nation beyond the state: diasporas as threats, victims, and assets

Securitization theory has paid extensive attention to transnational issues, actors, and processes. Surprisingly, however, only little attention has been paid to the securitization of diaspora communities, defined as overseas citizens or co-nationals abroad. This article fills this gap by developing an analytical framework to study the securitization of diasporas, focusing on three discursive formations: diasporas as threatening actors, as objects under threat, or as security resources. Building upon the recent literature on state–diaspora engagement and drawing on an analysis of Israeli elite discourse (from 1948 to 2022), this article demonstrates how the securitization of diasporas serves as a discursive mechanism that naturalizes and legitimizes extra-territorial policies towards Jews abroad. Thus, the article complements structural and rational explanations of state–diaspora engagement by examining the intersubjective process that endows diaspora policymaking with meaning. Against the backdrop of extensive securitization scholarship that focuses on attempts to keep “foreigners” out, this article shows how securitization justifies bringing certain people in or governing their national identity abroad.

Defending Civic Space: When are Campaigns against Repressive Laws Successful?

Many civil society organizations (CSOs) are fighting for survival as governments introduce legislation to curtail their activities. This article examines how domestic civil society campaigns can persuade parliamentarians to reject ‘anti-CSO’ legislation. We employ pairwise comparisons in two regions – East Africa and Central Asia – as well as process-tracing within four cases: two successful campaigns waged by CSO coalitions against repressive legislation in Kenya and Kyrgyzstan, and two unsuccessful campaigns in Uganda and Kazakhstan. We find that traditional structural explanations – most notably the degree of international linkage and leverage and the quality of democracy – play an important role in creating greater opportunities for domestic actors, but are not determinative. CSOs also need to take advantage of the more conducive environment to defend democracy. Doing so is more likely when campaigns: are pre-emptive and sustained, frame the issue in a manner that resonates with the electoral incentives facing parliamentarians, coordinate with influential international actors, and engage pragmatically with both the informal political rules that shape legislators’ behaviour and the formal procedural ‘mechanics’ of legislatures. The article therefore demonstrates the significance of both political structure and agency, and of international actors using their influence to create space for domestic groups, ‘leading from behind’.

Diachronic phonological typology: understanding inventory structure through sound change dynamics

Abstract We advocate for a diachronic typological approach to phonology, arguing that explanation for phonological structure must appeal to dynamic processes. We outline basic assumptions and explanatory mechanisms of this framework and demonstrate its utility by applying it to aspects of consonant phoneme inventory structure. Examining sound change paths through which palatal(ized) and ejective consonants emerge, we show that initial conditions in a language influence the likelihood of a sound change occurring, and that sound change trajectories may differ in their lifespans and the ease with which they are entered into. Regarding more general theoretical issues, we find that focusing on the dynamic processes that create inventories is more likely to produce accurate predictions about the patterns observed than structural generalizations such as feature economy. We conclude that further elucidating the details of sound change will lead to a fuller and more explanatory phonological typology.

Generating Real-Time Explanations for GNNs via Multiple Specialty Learners and Online Knowledge Distillation

Graph Neural Networks (GNNs) have become increasingly ubiquitous in numerous applications and systems, necessitating explanations of their predictions, especially when making critical decisions. However, explaining GNNs is challenging due to the complexity of graph data and model execution. Post-hoc explanation approaches have gained popularity due to their versatility, despite their additional computational costs. Although intrinsically interpretable models can provide instant explanations, they are usually model-specific and can only explain particular GNNs. To address these challenges, we propose a novel, general, and fast GNN explanation framework named SCALE. SCALE trains multiple specialty learners to explain GNNs, as creating a single powerful explainer for examining the attributions of interactions in input graphs is complicated. In training, a black-box GNN model guides learners based on an online knowledge distillation paradigm. During the explanation phase, explanations of predictions are generated by multiple explainers corresponding to trained learners. Edge masking and random walk with restart procedures are used to provide structural explanations for graph-level and node-level predictions, respectively. A feature attribution module provides overall summaries and instance-level feature contributions. We compare SCALE with state-of-the-art baselines through quantitative and qualitative experiments to demonstrate its explanation correctness and execution performance. Furthermore, we conduct a user study and a series of ablation studies to understand the strengths and weaknesses of the proposed framework.

Using enactive robotics to think outside of the problem-solving box: How sensorimotor contingencies constrain the forms of emergent autononomous habits.

We suggest that the influence of biology in 'biologically inspired robotics' can be embraced at a deeper level than is typical, if we adopt an enactive approach that moves the focus of interest from how problems are solved to how problems emerge in the first place. In addition to being inspired by mechanisms found in natural systems or by evolutionary design principles directed at solving problems posited by the environment, we can take inspiration from the precarious, self-maintaining organization of living systems to investigate forms of cognition that are also precarious and self-maintaining and that thus also, like life, have their own problems that must be be addressed if they are to persist. In this vein, we use a simulation to explore precarious, self-reinforcing sensorimotor habits as a building block for a robot's behavior. Our simulations of simple robots controlled by an Iterative Deformable Sensorimotor Medium demonstrate the spontaneous emergence of different habits, their re-enactment and the organization of an ecology of habits within each agent. The form of the emergent habits is constrained by the sensory modality of the robot such that habits formed under one modality (vision) are more similar to each other than they are to habits formed under another (audition). We discuss these results in the wider context of: (a) enactive approaches to life and mind, (b) sensorimotor contingency theory, (c) adaptationist vs. structuralist explanations in biology, and (d) the limits of functionalist problem-solving approaches to (artificial) intelligence.

Where is the pain? A qualitative analysis of Ghana's opioid (tramadol) 'crisis' and youth perspectives.

Over the last five years, media reports in West African countries have suggested a tramadol abuse 'crisis' characterised by a precipitous rise in use by youth in the region. This discourse is connected to evidence of an emerging global opioid crisis. While the reported increase in tramadol abuse in West Africa is likely true, few studies have critically interrogated structural explanations for tramadol use by youth. Nascent academic literature has sought to explain the rise in drug use as a function of moral weakness among youth. This Ghanaian case study draws on primary and secondary data sources to explore the pain that precedes tramadol abuse. Through a discourse analysis of 295 media articles and 15 interviews (11 with youth who currently use tramadol and 4 with health system stakeholders), this study draws on structural violence and moral panic theories to contribute to the emerging literature on tramadol (ab)use in West Africa. The evidence parsed from multiple sources reveals that government responses to tramadol abuse among Ghanaian youth have focused on arrests and victim blaming often informed by a moralising discourse. Interviews with those who use tramadol on their lived experiences reveal however that although some youth use the opioid for pleasure, many use tramadol for reasons related to work and feelings of dislocation. A more complex way to understand tramadol use among young people in Ghana is to explore the pain that leads to consumption. Two kinds of pain; physical (related to strenuous work) and non-physical (related to anxiety and the condition of youth itself) explain tramadol use requiring a harm reduction and social determinants of health approach rather than the moralising 'war on drugs' approach that has been favoured by policy makers.

The Isoleucine at Position 118 in Transmembrane 2 Is Responsible for the Selectivity of Xamoterol, Nebivolol, and ICI89406 for the Human β1-Adrenoceptor.

Known off-target interactions frequently cause predictable drug side-effects (e.g., β1-antagonists used for heart disease, risk β2-mediated bronchospasm). Computer-aided drug design would improve if the structural basis of existing drug selectivity was understood. A mutagenesis approach determined the ligand-amino acid interactions required for β1-selective affinity of xamoterol and nebivolol, followed by computer-based modeling to provide possible structural explanations. 3H-CGP12177 whole cell binding was conducted in Chinese hamster ovary cells stably expressing human β1, β2, and chimeric β1/β2-adrenoceptors (ARs). Single point mutations were investigated in transiently transfected cells. Modeling studies involved docking ligands into three-dimensional receptor structures and performing molecular dynamics simulations, comparing interaction frequencies between apo and holo structures of β1 and β2-ARs. From these observations, an ICI89406 derivative was investigated that gave further insights into selectivity. Stable cell line studies determined that transmembrane 2 was crucial for the β1-selective affinity of xamoterol and nebivolol. Single point mutations determined that the β1-AR isoleucine (I118) rather than the β2 histidine (H93) explained selectivity. Studies of other β1-ligands found I118 was important for ICI89406 selective affinity but not that for betaxolol, bisoprolol, or esmolol. Modeling studies suggested that the interaction energies and solvation of β1-I118 and β2-H93 are factors determining selectivity of xamoterol and ICI89406. ICI89406 without its phenyl group loses its high β1-AR affinity, resulting in the same affinity as for the β2-AR. The human β1-AR residue I118 is crucial for the β1-selective affinity of xamoterol, nebivolol, and ICI89406 but not all β1-selective compounds. SIGNIFICANCE STATEMENT: Some ligands have selective binding affinity for the human β1 versus the β2-adrenoceptor; however, the molecular/structural reason for this is not known. The transmembrane 2 residue isoleucine I118 is responsible for the selective β1-binding of xamoterol, nebivolol, and ICI89406 but does not explain the selective β1-binding of betaxolol, bisoprolol, or esmolol. Understanding the structural basis of selectivity is important to improve computer-aided ligand design, and targeting I118 in β1-adrenoceptors is likely to increase β1-selectivity of drugs.

Recent Synergies of Machine Learning and Neurorobotics: A Bibliometric and Visualized Analysis

Over the past decade, neurorobotics-integrated machine learning has emerged as a new methodology to investigate and address related problems. The combined use of machine learning and neurorobotics allows us to solve problems and find explanatory models that would not be possible with traditional techniques, which are basic within the principles of symmetry. Hence, neuro-robotics has become a new research field. Accordingly, this study aimed to classify existing publications on neurorobotics via content analysis and knowledge mapping. The study also aimed to effectively understand the development trend of neurorobotics-integrated machine learning. Based on data collected from the Web of Science, 46 references were obtained, and bibliometric data from 2013 to 2021 were analyzed to identify the most productive countries, universities, authors, journals, and prolific publications in neurorobotics. CiteSpace was used to visualize the analysis based on co-citations, bibliographic coupling, and co-occurrence. The study also used keyword network analysis to discuss the current status of research in this field and determine the primary core topic network based on cluster analysis. Through the compilation and content analysis of specific bibliometric analyses, this study provides a specific explanation for the knowledge structure of the relevant subject area. Finally, the implications and future research context are discussed as references for future research.

The squeaky wheel gets the grease: Violent civil unrest and global social assistance provision.

What are the contemporary determinates of social assistance provision? What is the role of contentious politics? Social assistance literature is dominated by economic and demographic accounts, which under-examine the possibility that governments extend social assistance to contain social unrest. We test factors associated with these “structuralist” and “political” theories on a new panel dataset which includes 54 OECD and emerging market countries between 2002 and 2015. The results indicate social assistance coverage has a significant positive relationship with riots. We explain this outcome as policymakers expanding social assistance as a means of containing violent civil unrest. This effect is more significant in emerging markets, suggesting that the domination of structural explanations is a result of sample bias toward the OECD. Finally, we find that governments consider World Bank social policy recommendations only insofar as there is violent unrest.

Design and Development of a Mathematical Model for an Industrial Process, in a System Dynamics Environment

This research proposes a methodology based on control engineering, transforming the simulation model of system dynamics into a mathematical model expressed as a system transfer function. The differential equations of a time domain present in the Forrester diagram are transformed into a frequency domain based on the Laplace transform. The conventional control engineering technique is used to present and reduce the dynamic system in a block diagram as a mechanism for determining the structure of the system. The direct path equation and the feedback equation are determined to obtain mathematical models that explain the trajectory of the behavior of each state variable through a transfer function in response to the different inputs of the system. The research proposal is based on presenting an alternative of analytical validation for more robust decision-making to systems dynamics models, based on the explanation of the system structure through a transfer function and its analysis of stability and external controllability for the system dynamics model under study. The results are visually analyzed in a root diagram.

Dependence of film structure on the film structure-independent equivalent film thickness in magnetron sputtering deposition of Ag thin films

In this work, I have investigated the structures and properties of Ag thin films deposited by magnetron sputtering onto glass substrates with temperatures of 150 and 600 °C for film structure-independent equivalent film thicknesses in the range of 20–400 nm. The Ag thin film morphologies observed using scanning electron microscopy and atomic force microscopy showed the following distinguishable changes: an Ag thin film with an equivalent film thickness of 20 nm deposited at a substrate temperature of 150 °C displayed a film microstructure of oblate grains separated by voids, while those with equivalent film thicknesses of 50 nm or more displayed microstructures consisting of flat-topped grains without any obvious voids between them. In comparison, an Ag thin film with an equivalent film thickness of 20 nm deposited at a substrate temperature of 600 °C displayed a microstructure consisting of isolated spherically shaped grains with a uniform diameter of approximately 40 nm and spaced at uniform intervals; an Ag thin film with an equivalent film thickness of 50 nm displayed a microstructure of more oblate grains; Ag thin films with equivalent film thicknesses of 100 and 200 nm displayed microstructures of highly isolated, flat-topped, mound-shaped grains; and an Ag thin film with an equivalent film thickness of 400 nm displayed a microstructure of continuous flat-topped, mound-shaped grains. In addition, the Ag thin films with equivalent film thicknesses of 20 and 50 nm deposited at 600 °C exhibited higher compressive stresses. The quantitative results of optical-transmittance and electrical resistivity measurements were consistent with the changes in thin film morphology. The morphological structures of the Ag thin films deposited at 600 °C result from the high surface diffusivity of the Ag atoms, which do not wet the glass substrate, whereas the morphologies of the Ag thin films deposited at 150 °C result from in-place grain growth following the formation of multiple nuclei because of the low surface diffusivity of the Ag atoms at this temperature. The observed thin film microstructures are unexplained by the classical structure model for sputter-deposited metal thin films, which does not consider either the high surface diffusivity of adatoms that do not wet the substrate or the increase in surface area required to dissipate the energy accumulating in grains during film deposition. The results obtained in this study provide a fundamental description and explanation of the grain structure of metal thin films with thicknesses of a few tens of nanometers or less.

Regime Change and Malaysia–South Korea Relations: Domestic and Structural Explanations of Mahathir Mohamad and Moon Jae-in’s Foreign Policy Reorientations

The idea that a change of government can alter the foreign policy orientation of a state is nothing new in international relations. This paper presents a preliminary investigation into the causal linkages between domestic political regime changes and foreign policy restructuring in Malaysia and South Korea. It assumes that regime changes allow for a greater propensity for the recalibration of foreign policy interests. Since the effectiveness of any bilateral cooperation depends on successful formulation and implementation, this paper dissects the transition, convergence and challenges in bilateral cooperation between the two countries. Both Mahathir Mohamad and Moon Jae-in saw a necessity to diversify economic partners that had resulted from the policies of previous administrations. While the basic elements of their foreign policy remained the same, both Malaysia and South Korea reevaluated their policies with regard to the international issues affecting their domestic interests. While relations had once been transactional at best, the convergence of the Look East Policy (LEP) 2.0 and the New Southern Policy (NSP) advanced bilateral relations for 22 months until the collapse of Mahathir’s government in 2020.

Developing e-Book of Reading for Intensive Course in Virtual Classroom: Students’ Need Analysis

This research clarifies the demands of students through need analysis concerning the content of e-book of reading for Intensive Course in virtual classroom, and the questionnaire was distributed to one hundred and twelve (112) students of English Study Program of FKIP University of Palangka Raya to explore the necessity. The results showed that most students require: first, reading texts as instructional materials which are accompanied by English grammar and English expressions to lead students to expose both oral and written English in daily life communication with other people using ICT (100%). Second, reading texts consist of 200-250 words (87.50%) which covered the topics of daily life and Dayak culture themes (.90%). Third, reading activity is to do reading a text and looking for detailed information (88.39%), and speaking activity is to discuss the exercises and tasks with peers (88.39%). Forth, writing input is about the explanation of the sentence structure used in the text, and writing activity that led them doing writing practice to write a text similar to the example given using their own sentence (82.84%). Fifth, learning activity on vocabulary and grammar cover pairing words with their meaning (89.28%), and write sentences according to the given pattern (100%). Last, the lecturer’s role acts as motivator and learners’ role are as responsive participants, and setting takes in virtual classroom or online learning. These signify student’s needs most which are as the basis for designing and developing e-book later.